(1) Field of the Invention
This invention relates to the generation, display and manipulation of information on a computer display screen. Specifically, the field is that of the display and manipulation of depictions of icons on a display screen representing the variable contents of a document or application file or a folder of files.
(2) Prior Art
One significant feature of modern computer systems is the ability for a computer user to be able to easily access information and programs available for use on the computer system. One way that the access to information and programs has been facilitated is through the development of graphical user interfaces. Computer systems using a graphical user interface typically provide the capability to display icons on the computer display screen. Icons are small graphical images displayed on the screen that represent certain objects accessible to the computer user, such as files of information, documents, programs, or file folders. Icons can also represent certain actions which are being or could be performed by the computer, such as an icon representing a find command or a trashcan icon representing a delete command.
The use of icons to represent objects is particularly useful, since the operator can quickly identify a particular object simply by the shape and appearance of the icon. Icons can be manipulated in a number of different ways, although the most typical is through use of a cursor control device (i.e., mouse) and a selection button located on the mouse. By manipulating an icon, the computer user can access information, activate a program, or gain information about a document or program, such as the size of the document, the date of last modification, or the version number of the program. Icons are also useful in identifying programs or documents of a similar type. Due to their small size relative to the size of the display screen, many icons can be displayed at one time. Icons can also generally be moved to any location on the display screen, thereby maximizing the area available for the display of information. One well known system for displaying and manipulating icons is embodied in the Apple.RTM. Macintosh.RTM. computer system manufactured and distributed by Apple Computer, Inc., Cupertino, Calif.
Folders are collections of documents or programs represented by a single folder icon. Just as with document or program icons, the user can manipulate the folder icon to learn information about the folder, such as the size of the folder, or the date that the folder was last modified. Also, by manipulating a document or program icon, the user can move a document or program into a folder by selecting the document or program icon and moving the icon within the folder icon. In this way, the user can readily create collections of programs or documents within a folder. Similarly, one folder can be moved into another folder by selecting a first folder icon and moving the icon into a second folder icon. This feature allows the computer user to create a hierarchical collection of programs and documents within folders.
Icons are typically displayed in prior art graphical user interface systems as a static array of dots (pixels) on the display screen. This array of pixels, known as an icon image, is typically associated with the type of document or program represented by the icon. Other implementations associate an icon image with a document, depending upon the type of program used to manipulate the document. For example, documents created with certain word processing applications are represented by an icon image depicting a generic page of text or an image identifying the type of word processor used to create the document. In either case, the generic icon image is assigned at the time the program creates the document, and is not typically modified thereafter, thereby making it impossible for the icon image to represent changes in the content of the document. Similarly, folders are typically identified with an icon image depicting a small file folder. The folder icon conveys to the user the simple fact that the folder exists; but, it doesn't attempt to identify the content of a particular folder.
Although icons provide a quick way of conveying information to the user, they are limited by their small size. Since many icons may need to be displayed on the display screen simultaneously, the typical implementation for an icon image is limited to a square array of a small number of pixels. Graphical images of this size limit the type and scope of information that can be conveyed to the user. Moreover, the prior art method of using fixed icon images, depending upon the type of document or program, does not provide a way to distinguish between two documents or programs of the same type. Further, folder icons do not provide a mechanism for displaying the contents of a particular folder.
Some forms of icon animation have been used in the prior art to convey information to the user about an application or document. Icons are animated by changing the icon image over time to produce an illusion of image motion. Icon animation removes the limitation of using only a fixed array of pixels for an icon image while maintaining the size constraints of the icon as displayed on the display screen. Animation in the prior art is implemented by displaying a series of fixed frames. Each frame depicts the icon image at some instant in time. These fixed frames are produced by either manually creating a plurality of fixed icon images in various stages of motion or by digitizing a number of frames from an analog clip of video. This latter process produces icon-like, or small window-sized, images generally known as "dicons" (dynamic icons) or "micons" (movie icons). Either process is typically time-consuming and generally requires expensive additional equipment and/or software. Neither process is effective, nor suited, for depicting changes in the content of the object to be dynamically represented by the animated icon.
Some software applications allow the normally full-sized window in which the content of the document is being displayed to be reduced in size so that the user can simultaneously use other documents or carry out other tasks while the document is being displayed. Most of these applications do not actually shrink the text or images within the window as the window is being reduced. Hence, all the program really does is reduce the portion of the document that can be viewed and not recreate the document in a different form. Other software applications reduce the content of the entire document to fit within the new smaller display window, but such programs are only operative to carryout this technique when the program corresponding to the document in also running on the computer. Hence, to view the document is this reduced form, it would first be necessary to start the program and then take whatever additional steps that are necessary to cause the program to shrink the contents of the document.
To be useful, and certainly in the context of a desktop computer interface, icon animation images must have a close relationship to the object and the content of the objects that they represent, but be independent of their underlying programs. Hence, the process for generating the animation images must be as flexible and robust as possible, which are requirements not met by such prior art tools and methods.